Update to new gr-osmosdr header structure.
Fill area under FFT plot with gradient.
Add color picker widget.
Widgets for selecting FFT color and fill.
Add support for changing FFT plot colors.
Connect FFT color signals to plotter.
Updated predefined colors.
Update audio FFT color and fill when changing FFT settings.
Update info.
Use functions to set initial plot settings.
Change frequency display concept.

Due to user demand the main frequency control and display widget now displays
the receiver frequency and not the hardware frequency. Changes to the shown
frequewncy will still lead to hardware tuning though, but now taking the filter
offset into account.
Allow FFT plot to fill 100%.
Update center frequency when LNB LO is changed.
Fix incorrect tuning when using LNB LO.

Fixes the wrong behaviour introduced by commit 58b527320cabe19c15d84373e750747681dd29ce
and later.
Update tooltips.
Add P25 decoding

A patched version of the OP25 project is needed to install some needed
functions.  Testing was conducted with a RTLSDR device with an E4000
tuner.  Even with your ppm entered, at higher frequencies your device
may still be off by a small amount.  Set the filter to "Wide" if
"Normal" doesn't work.
Remove dependence on some unexported code from OP25

Use the digital M-PSK clock/phase recovery block rather than the
modified Costas loop from the OP25 repeater code.
Add OP25 patch needed for P25 reception